A vehicle autonomously travelling without an onboard operator, so-called unmanned ground vehicle, is known as a haulage vehicle for carrying ore and/or earth and gravels excavated at a surface mine and/or the like. The unmanned ground vehicle requires the calculations of an own-vehicle position to travel autonomously. From this perspective, known processing for own-vehicle position calculating systems comprises inertial-navigation operation processing using output from a GPS (Global Positioning System) and/or an IMU (Inertial Measurement Unit).
Patent Literature 1 discloses, as travel control technologies of unmanned ground vehicles using own-vehicle positions, the configuration that sets a target vehicle speed of a unmanned ground vehicle to be smaller than a predetermined vehicle speed as the amount of positional departure between a target position on a pre-decided travel route on which the unmanned ground vehicle travels and a current position of its own vehicle becomes large.